European published patent specification No. EP-B.sub.2 -002141 describes an in-ground storage facility which is made on site using prefabricated elements which are essentially constituted by concrete bins. Each bin has a far wall and three side walls. The bins are laid against one another in successive courses like bricks in a previously dug cylindrical hole, thereby building a circular wall around a central spiral staircase. In an in-ground facility designed in this way, the far walls of the bins constitute the outer wall of the facility itself, and the bins are on the inside relative to said wall.
The main aim of the present invention is to provide a structure for an in-ground storage bin facility in which the bins are spaced apart from one another with each bin being surrounded by earth on at least three of its faces, and may be surrounded on five of its faces, with an open access face being inwardly directed towards the inside of the facility.
A secondary aim of the invention is to provide a structure of the above-defined type which is designed in such a manner as to be capable of being prefabricated in a workshop or factory, of being stored and transported easily, and finally of being rapidly installed on site in a hole that has been dug to receive it.